<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../reactBag/react.development.js"></script>
    <script src="../reactBag/react-dom.development.js"></script>
    <script src="../reactBag/babel.min.js"></script>
</head>

<body>
    <div id="app"></div>

    <script type="text/babel">

        class App extends React.Component{
            state = {
                change : 0
            }
            render(){
                const {change} = this.state;
                return <div>
                    
                        <button onClick = {this.fn}>点击加一</button>
                        <p>{change}</p>
                    </div>
            }
            fn = ()=>{
                let {change} = this.state
                this.setState({change : ++change})
            }
        }

        ReactDOM.createRoot(document.getElementById('app')).render(<App/>)
    </script>
</body>

</html>